of boston



No. 626,l46. Patented May 30, I899. H.-M CRANE &. T. C. WALES, JR.

TELEPHONE TOLL CIRCUIT.

\ (Application filed May 25, 1898.)

(No Model.)

UNITED STATES PATENT OFFICE.

HENRY M. CRANE, OF BOSTON, AND THOMAS C. WVALES, JR, OF NEWTON, MASSACHUSETTS, ASSIGNORS TO THE AMERICAN BELL TELEPHONE COM- PANY, OF BOSTON, MASSACHUSETTS.

TELEPHONE TOLL-CIRCUIT.

SPECIFICATION forming part of Letters Patent No. 626,146, dated May 30, 1899. Application filed May 25, 1898. Serial No. 681,724. (No model.)

To all whom it may concern.-

Be it known that we, HENRY M. CRANE, residing at Boston, in the county of Suffolk, and THOMAS C. WALES, J r., residing at Newton,

in the county of Middlesex, State of Massachusetts, have invented certain Improvements in Telephone Toll-Circuits, of which the following is a specification.

The present invention relates to toll trunkto ing-circuits which extend between operators in the same central station or between two telephone central stations, whereby the substation-circuits associated with the said station or stations may be placed in electrical connection with each other.

The invention is described in connection with the type of substation-circuits known as relay-circuits, in which the current-supply for the substation calling apparatus and tele- 2o phone-transmitters is located at the central office and wherein the signals between the different stations and operators are automatically operated. In such trunking-circuits the mode of operation is as follows: The sub- 2 5 scriber wishing a toll connection removes his telephone fromits switch, which, automatically actuated, closes the circuit, causing the line lamp-signal at the central station to be lighted. The subscribers operator takes the 0 call in the usual manner by inserting the answering-plug of a cord-circuit into the jack'ot the circuit and then inserts the other plug of the cord-circuit in the jack of an order-circuit extending to the switching operators 3 5 table, thereby causing a signal-lamp to be lighted at said table. The latter operator, listening at the order-circuit, takes the details of the call from the subscriber and then taken down. "The toll operator is now in formed by a ticket or otherwise of the numher of the called substation and of the number of the trunk plugged to the calling-circuit, and it is her duty to make the connec tion with a cord-circuit. Nowiffor any reason the toll operator fails or delays in making the connection the calling subscriber meanwhile has no means for attracting the attention of any operator and must wait until the connections so far made are taken down and his circuit restored to its normal condition before he can again signal an operator.

The object of the present invention is to provide means for overcoming this defect in the operation of the circuits and to render it at all times possible for the subscriber to signal to an operator and have the trouble rectified.

The invention also provides means whereby any substation-circuit will test busy at all of the operators tables to which it is multipled when a toll-circuit has beenplugged thereto whether the called-for-substation circuit has been completely connected or not.

The means whereby the invention is carried out will now be fully described, and pointed out in the appended claims.

The drawing, to which reference is made, is a diagram illustrative of the invention and shows two substation-circuits X and Y, terminating at a central-station. Each circuit consists of the conductors 1 and 2, provided with jacks J 2 and J, multipled at the tables of the operators, the conductors at the latter jack normally continuing by armature-levers 4 and 5 and wires 6 and 7, which are closed to one another and form a grounded loop, which includes the relay F and battery 0.

The armature 8 of relay F and its front con- 1 tact 24 are connected by the conductor 9,

v which includes battery I) and the line lampsignal H, while a branch 10 connects wire 9 to ground. Wire 3 connects the test-rings (t a to ground through the relay E. Both substation-circuits are alike; but only a portion of His shown. I

0 represents a toll trunk-circuit terminat-v ing at the end where the call is initiated in the plug P, from whose tip and sleeve contacts extend, respectively, the wires 14, 13, and 12. The wires 13 and 14 constitute (when the trunk is connected up) the talking-circuit, and between them are bridged the listening-key 70 and the branches 31 and 32'and 34 and 35, leading to the jacks J and J. The

wire 12 extends to ground through helix R of relay Q and battery (2, while the helix R of said relay is connected to ground on one side and to wire 15 on the other side. The said wire includes the relay S and has branches 30 to the test-rings of the jacks J and J The armature f of relay Q is connected by wire with the armature h, and from point 11 on wir 2O a'wire 21 extends to the front contact 22 of armature h, includingin its circuit the signal T. A wire 18 connects with wire 21 at point 33 and also with one side of the relay U, from whose other side wire 16 extends to the front contact 23 of armature f. The wire 18 includes battery 9.

The relay U has two armatures 2' i, or armature-contacts normally retracted to their back contacts 25 and 26, which are connected, respectively, with the conductors 14: and 13. A wire 38 unites the two armatures i 2' and includes serially the battery j and relay \V. The arn'iature m of relay is connected by the wire 28 with the grounded wire 29, having in its circuit battery n and lamp-signal K, controlled by the armature m.

L is an order-circuit between the subscribers operator and the switching operator and is provided at the former table with jack J and at the latter section with lamp-signal 1, battery (Z, listening-key 7c, and telephone.

\Ve have designated the ditferent operators tables or sections as A B O D and have spaced off the apparatus and circuits by dotted lines.

In the operation of the invention, supposing that the subscriber at- X wishes a toll connection, he removes his telephone from its hookswitch, which rises, closes the circuit through the battery 0, and energizes the relay-magnet F, which by attracting the armature S to its contact 21 closes the local circuit 9 and lights the lam p-signal 11. The operator at A inserts plug P of cord-circuit N into the jack J of the substation-circuit and receives the call and then inserts the other plug P into jack J of the order-circuit L closing the same and lighting the lamp-signal at the table B of a switching operator, who depresses the listening-key 71: in the order-circuit and takes the call from the subscriber. The number of the substation wanted, together with the number of the trunk 0, may be noted upon a ticket and transferred to the toll operator at section D, who accordingly completes the connection. This information may be conveyed to the toll operator by an order-circuit or by any other suitable means. The switching operator at B also inserts plug P into jack J of the calling-substation circuit, and its tip 50 makes conneetionwith thejack-spring 51, the sleevecontact (30 makes connection with the spring 61, and the sleeve-contact 70 connects with the test-ring a, and a current of, say, onetenth of an ampere fiows from battery 6 through winding R of relay Q, wire 12, sleeveeontact '70, test-ring a, and cut-off relay E to ground. This flow of current is insuflicient to cause the relay Q to attract its armature f,

but serves to charge the busy-test wire 3 of the substation-circuit throughout the switchboard and to attract armature-levers 4 and 5, thus breaking the circuit from conductors 1 and 2 through battery 6. The switching operator after receiving the subscribers call asks him to replace his telephone upon its hook, stating that he will be called when the connection is ready. Now it the instructionticket mentioned should be lost or for any reason the toll operator delays in making or fails to make the connection the waiting subscriber may call the attention of the operator at the 0 section to such neglectin the following manner: After waiting a due time without being called he lifts the telephone from the hook, and current flows from the battery 7', conductor 38, upper armature i of relayU,

conductor 14, tip of plug P", line-spring 51, conductor2 of circuit L, and back by 0011- ductor 1, line-spring (31, sleeve-contact of the plug, conductor 13, lower armature 2 of relay U, wire 38, and relay \V. This current causes the relay WV to attract its armature m to its contact 27, closing the local circuit Z and lighting the lamp guard-signal K. To answer the signal, the operator at O, who may be the chief operator, inserts plug P of the cord-circuit N into the trunk-jack J", and current flows from battery y in said cord-circuit via conductor 52, sleeve-contact 53, testring aZwires 30 and 15, relay S, and winding R of relay Q to ground. The resistances of this circuit are so proportioned that two-tenths of an ampere will flow through it, causing the armature f of relay Q to be drawn up to the contact 23 and the armature h of relay S to be drawn up to its contact 22. \Vhen the armatures f and h are thus drawn up, current flows from battery g through wire 18, cut-oft relay U, wire 16, armatu ref, wire 21, and signal T to battery; but as the signal T is shunted by the wire 20, connecting point 11 with armature h and point 33, the signal T is not operated, the current from battery g energizes relay U, and the armatures i are drawn thereto and away from their contacts 25 and 26, whereupon the armature m falls away from contact 27, and the lamp-signal K is extinguished. The relay U by drawing armatu res t' 11 away from contacts 25 and 2e removes the bridge connection between conductors 13 and 14- by way of said armatures, batteryj, relay 1V, and wire 38. Said bridge connection, if not moved or rectified, would constitute an obstruction in the talking-circuit between the operator D and the subscriber X. The chief operator can now communicate with the subscriber and remedy the trouble. If the said ticket has not been destroyed or lost while on its way from the switching to the toll operator or if the call is attended to in due course, the toll operator inserts plug P of cord-circuit N into the jack J of the designated truck-circuit, and current from batteryac flows via cord 54, plug-contact 55, test-ring (1 wires 30 and 15, relay S, and winding R of relay Q. The

Q N Avail armaturesf and h of relays Q and S are drawn up, and current from battery g operates relay U, but does not operate signal T, the results being the same as described of the act of inserting plug P into the jack J The relay U by drawing its armaturesi i away from contacts 25 and 26 removes the bridge connection between conductors 13 and 14 by way of said armatures, battery j, relay W, and wire 38. Said bridge connection, if not removed or rectified, would constitute an obstruction in the talking-circuit finally established between the subscribers. The toll operator now inserts the second plug P of the cord-circuit into jack J 6 of the called-for line and proceeds to complete the connection in a well-known manner. The disconnecting-signal for the circuit thus made up is in the cord-circuit N of the toll operator, and when this is operated by either subscriber hanging his telephone on its hook the said operator withdraws the plug P from the jack J and plug P from jack J Current then ceases to flow through relay S and winding R of relay Q, and arma ture h of the former relay falls back; but the armature f of relay Q remains attracted, for while the current from battery e is not strong enough to attract armature f it is sufficient to hold it up. When the armature it fell away from contact 22, the portion of current from battery 9 which flowed in the shunt 20 was united to that flowing through the signal T, which caused the signal to operate and indicate to the switching operator at B that the circuit is to be disconnected, She therefore withdraws the plugP" from the jack J and thereupon the armature f of relay Q falls away and opens the' circuit, including the signal T and the relay U, which then resume their normal positions.

The invention has been described in association with a toll-circuit O, by means of which the substation-circuits L and L are directly connected with each other; but it willbe understood that if the circuit 0 should be connected to an outgoing toll-line terminating at a distant point, which line should then be connected with a substation-circuit,

such an extension would be within the scope of the invention and it is indeed our purpose to thus employ it.

\Ve claim as our invention 1. The combination with a toll tru nki'ng-circuit, multipled to a plurality of switchboardsections, provided with means for connecting two substation-circuits together and to energize their test-circuits and also its own; of an automatic disconnecting-signal at the first of said sections; and means at the second sec-- tion, whereby when a calling-substation circuit has been connected to the trunking-circuit the subscriber at the substation is enabled to signal the operator at said section, substantially as and for the purpose set forth.

2. The combination in a toll trunking-circuit multipled to a plurality of switchboardtwo substation-circuits together, and to energize their test-circuits and also its own; of an automatic disconnecting-signal at the first of said sections; with means at the second section, whereby when a calling-substation circuit has been connected to the trunkingcircuit the subscriber at the substation is enabled to signal the operator at the said section, said means consisting of a normally-closed shunt between the main conductors of the trunk-circuit including a battery and a relay, the latter adapted to close a local circuit and operate a signal, substantially as specified herein.

3. The combination in a toll trunking-circuit multipled to a plurality of sections at which sections three distinct operative functions are performed; of means at the first section for receiving a call from a substation and for switching the trunk-circuit thereto, means at the second section for rectifying obstructions in the circuit so made up, and means at the third section for connecting the trunkcircuit to the called-for circuit; with an automatic disconnecting-signal at the first section, as set forth.

4. The combination in a toll trunking-circuit multipled to a plurality of switchboardsections at which sections three distinct operative functions are performed; of means at the first section for receiving a call from a substation, for switching the trunk-circuit thereto, and for energizing its test-circuit, means at the second section for rectifying obstructions in the circuit so made up consisting of a signal adapted to be operated by the calling-substation, and an operators telephone outfit, and of means at the third sta tion for connecting the trunk-circuit to the called-for-substation circuit and for energizing its own and the said substation-circuits test-circuit, substantially as set forth.

5. The combination with a toll trunkingcircuit multipled to a plurality of switch board-sections provided with means for connecting two substations together consisting of a plug-terminal at one section, and a springjack and cordcircuit at another section, and with means at both sections to energize the several test-circuits concerned; of means for section, the said means consisting of a doublewound relay, one winding of which is connected from ground through a battery to the testring contact of the said plug, the second winding being connected through an auxiliary relay to the test-conductor of the trunk, said 1 relay being adapted to render the disconnecting-signal inoperative when the called-substation circuit is connected to the trunk, and to cause it to become operative when the said circuit is disconnected therefrom.

6. The combination in a toll trunking-circuit multipled to a plurality of switchboard sections, ofmeans at the first section for receiving a call from a substation, and for sections, provided with means for connecting switching the trunk-circuit thereto, and for operating a disconnecting-signal at the first energizing the test-circuit thereof, and also for receiving a disconnecting-signal, the same consisting of a three-contact plug-terminal, and a double-wound relay, one winding of which is connected from ground through a battery to the test-ring contact of the plug, the other winding being connected through an auxiliary relay to the test-conductor of the trunk and adapted to operate a disconnecting-signal; means at the second section for rectifying obstructions in the circuit so made up, and means at the third section for connecting the trunk-circuit to the called-forsubstation circuit; for rendering the said disconnecting-signal inoperative and for causing it to become operative when the said circuit is disconnected, as set forth.

7. The combination in an organized telephonecircuit, of a substation-circuit multipled to a plurality of switchboard-sections and provided with an automatic line-signal; a toll trunking-circuit having a plug-terminal at its call-receiving section, terminal switches at a plurality of switchboard-sections, and means for connection with a calledfor substation; with means at an intermediate switchboard-section, whereby when a callingsubstation circuit has been connected to the trunking-circuit, the subscriber at the substation can signal the operator at said section; as set forth.

In testimony whereof we have signed our names to this specification, in the presence of two subscribing witnesses, this 12th day of May, 1808.

HENRY M. CRANE. THOMAS C. WALES, JR. \Vitnesscs:

Guo. WILLIS PIERCE, FRANK O. LocKWooD. 

